Then you've probably didn't upgrade it to Beta when it was necessary some years ago.
There used to be a link earlier to do this yourself but it was removed some time ago. Janus has to do that manually himself now, so you have to wait.
____________Life is Science, and Science rules. To the universe and beyond
Proud member of BOINC@HeidelbergMy BOINC-Stats

One technical detail that may be important (?) : I do this under a win7 virtual machine (on my iMac), in order to "feed" my office PC where boinc is not allowed to access internet (very restrictive proxy).

One technical detail that may be important (?) : I do this under a win7 virtual machine (on my iMac), in order to "feed" my office PC where boinc is not allowed to access internet (very restrictive proxy).

Well, that's of course an important detail. If this host is restricted to internet access you can only use it when the restriction is open for access.
Even if you do it for years, are you even allowed to run BOINC on this host? You can get trouble if you aren't, you know? Internet security isn't the same anymore.
____________Life is Science, and Science rules. To the universe and beyond
Proud member of BOINC@HeidelbergMy BOINC-Stats

Yeah be careful and make sure that you are allowed to do that. You wouldn't be the first person to loose their job over something like that.

Anyways, if you are certain that it is ok: Check that you have the newest BOINC version - specifically make sure that you have the newest version of ca-bundle.crt in C:/Program Files/BOINC. People from WCG had the same issue a little while ago.
Maybe you need a fix from 7.6.33.